Rotating control devices (RCDs) are used to isolate the annulus, contain annular fluids under pressure, and divert returns to pressure control and fluid management systems. RCDs connect to the top of the blowout preventer (BOP) in the wellhead, and allow rotary drilling and stripping out of a well with positive annular pressure. All RCDs include a sealing element which forms either a passive or active pressure seal around the drill pipe. The RCD is an important element in every managed pressure drilling and underbalanced drilling operation because neither application is possible without one.
The seal element must be flexible enough to allow pipe joints to pass through the RCD while maintaining a seal around the drill pipe. Conventionally, elastomeric seals such as rubber or polyurethane seals are used, which provide the needed flexibility. The seals conventionally have a steel core or frame which provides strength and rigidity.
Improvements in sealing performance will improve the function of RCDs, such as when used in managed pressure and underbalanced drilling.